Cathy, Afraid you are in for a tough time finding the three you have mentioned.Here is what I checked:
Texas Death Index Online 1964-1998.There was no Charles D. Kennedy that died in Harrison County, Texas during that period.There was a Charles J. Kennedy that died in Harrison County 26 Jul 1971 but he was not married toHelen. There was a James M. Kennedy that died in Hidalgo County (near Brownsville, TX.) 2 Oct 1976. There is no way to know if either of these Kennedy's are yours.
Texas Birth Index Online 1926 - 1949 There were no children born to Charles D. Kennedy or to Charles J. Kennedy with a wife the name of Helen.There were no children born to either with the names Joy, Joyce, Alice, or Billie.I also checked the same index for births with the father James M. Kennedyand the mother with the first name Ovie.There were no births during that period.